The invention concerns a teat cup liner for use in a milking cup with a head part that has an insertion opening for a teat of an animal and with a shaft part connecting to the head part, as well as a milking cup.
A milking machine that has several milking cups is used for milking an animal, especially a cow, with a machine. As a rule, the milking cups are connected to a collecting unit through milk tubes. The milked milk is transferred to a milk tank from the collecting unit. In connection with the milking of an animal, it is also known that one can use milking cups that are connected directly to a line of the milking system, and in this case a collecting unit is not used.
The milking cup comprises a sleeve in which a teat cup liner is arranged. A teat cup liner, also called molded milking tube, may have different designs. For example, according to WO 2005/070197, a teat cup liner is used on a milking cup with a head part on which a sealing lip is provided that forms an insertion opening for the teat. The head part is connected to a shaft part.
In the predominant majority of the known embodiments of a teat cup liner, this is made of one piece. Since the shaft part of the teat cup liner is brought to into contact with the teat, it is expedient to make the shaft part from a flexible material. Moreover, it is a requirement that the teat cup liner should be able to be cleaned easily and be compatible with the food product, the milk.
A teat cup liner made of a soft material, especially of silicone, has many advantages. However, it was found that, at the pairing of sleeve and teat cup liner, the teat cup liner may become damaged when forces, especially suddenly applied forces, are applied to the head of the teat cup liner. The sleeve is surrounded by a rim of the teat cup liner, through which damage to the teat cup liner may arise. This problem has already been recognized. In order to solve the problem, according to EP 0 477 950 A1, it is proposed that a recess be provided in the part of the holding rim lying opposite to the longitudinal and outward-facing part of the edge of the milking cup. A ring is inserted into the recess which is made of a material other than the material of the teat cup liner. Through this measure, the puncture behavior of the holding rim is supposed to be improved. A teat cup liner with a head part that has a holding rim for encompassing a milking cup sleeve is known from DE 196 35 719. The wall of the head part is stiffened between an insertion opening for the teat and a transition part, in the holding rim region. A part of the teat cup liner head that lies between the stiffened part and the holding rim is made to be elastic, at least partly. An attachable ring is provided on the edge of the milking cup sleeve that faces the head part of the teat cup liner. The ring has an edge that is displaced in the radial direction toward the outside and runs essentially in the longitudinal direction of the milking cup sleeve. An annular recess is provided in the holding rim of the teat cup liner in order to hold the ring.
In such an arrangement, the mounting of the milking cup represents a problem. It involves a not-insignificant expenditure. First the holding ring is placed on the rim of the milking cup. Then the head of the teat cup liner is placed onto the sleeve. Then the sleeve with the holding ring is moved in the direction of the head far enough, so that the lower part of the teat cup liner protrudes from the sleeve.
It is also known that, in order to improve the lifetime of the teat cup liner, the region of the teat cup liner that comes into contact with the edge of the sleeve can be made into a thicker ring. However, this has the disadvantage that the head of the teat cup liner will become correspondingly large, which represents a problem, especially when milking animals whose teats are close together.